Tuning the near-gap electronic structure of Cu2O by anion–cation co-doping for enhanced solar energy conversion

Dopingis an effective strategy to tune the electronic properties of semiconductors, but some side effects caused by mono- dopingdegrade the specific performanceof matrixes. As a model system to minimize photoproduced electron-hole pairs recombination by anion–cation co- doping, we investigate the electronic structures and optical properties of (Fe+N) co- dopedCu2O using the first-principles calculations. Compared to the case of mono- doping, the FeCuNO (a Fe (N) atom substituting a Cu (O) atom) co- dopingreduces the energy cost of dopingas a consequence of the charge compensation between the iron and nitrogen impurities, which eliminates the isolated levels (induced by mono-dopant) in the band gap. Interestingly, it is found that the contributions of different host atoms (Cu and O) away from anion (N) and cation (Fe) dopants to the variation of near band gapelectronic structure of the co- dopedCu2O are different. Moreover, co- dopingreduces the band gapand increases the visible-light absorption of Cu2O. Both band gapreduction and low recombination rate are critical elements for efficient light-to-current conversion in co- dopedsemiconductor photocatalysts. These findings raise the prospect of using co- dopedCu2O with specifically engineered electronic properties in a variety of solar applications.